This invention relates to tooth straightening and retention appliances and a method for their use.
Removable orthodontic appliances are well known and a number of different constructions are disclosed in my prior patents such as U.S. Pat. Nos. 3,848,335; 3,898,736; 3,939,598; 3,950,851; 4,073,061; 4,139,944; 4,784,605; 4,799,884; 4,830,612; 4,898,535; 4,919,612; 5,037,294; 5,037,295; D323,215; 5,203,695; 5,645,420 and 5,876,199.
My previous removable appliances have been constructed with particular uses in mind including use by children having a deciduous dentition, mixed dentition and permanent dentition. Some of the appliances have provided for self opening of the appliance. Also, some appliances are intended to be worn at night. However, it would be an improvement if such appliances included features which would assist the appliance in adhering better to the wearer""s teeth, as well as further assisting the opening of the appliance to permit breathing through the mouth, if necessary, to reduce the tendency for the appliance to be ejected from the mouth during sleep. It would also be an improvement if such an appliance were useful in correcting conditions such as overbite, overjet and crowding, and could be used prior to, during and after the application of fixed appliances such as braces.
The present invention provides an improved removable preformed appliance which is made of extra-soft material with a large amount of plasticiser in it, which makes it very soft and sticky. This material construction allows the appliance to be stretched over crooked teeth and to be able to stick to the dried off teeth to adhere better than previous appliances. The appliance has an upper trough and a lower trough connected at a rear end with an openable hinge and the opposed surface of the troughs include several raised bumps or other surface features so that the two opposed surfaces are not completely planar. The surface features prevent a suction from forming between the opposed trough walls when the patient opens his or her mouth while sleeping. If a suction did form, the easy opening of the appliance when the mouth opens would be prevented. Thus, the surface features assist in the self opening of the appliance which makes the appliance easier to wear, assists in breathing through the appliance allows for better retention to the crooked teeth, and prevents the appliance from slipping out of the mouth at night while the patient is sleeping.
The extra-soft material of the appliance allows the appliance to be able to stick to the teeth while the patient is sleeping which permits the appliance to exert pressure on the teeth all night so the teeth can be straightened out from their rotated and crowded positions.
The appliance is constructed so that it does not extend rearward to cover the most posterior teeth, namely, the first and second permanent molars which erupt at ages 6-7 years (first permanent molars), and at ages 12-13 years (second permanent molars). This shortening of the appliance at the posterior end allows the erupting teeth to over erupt and automatically open the bite, thereby correcting a deep overbite. Since this overbite is the most difficult problem to correct in orthodontics, and is extremely time consuming, it saves about one year of active (with fixed braces) treatment. Several different sizes of the preformed appliance are provided, as described in my prior patents, and a proper sized appliance is selected for a particular patient.
The present appliance, in an embodiment, also arranges the lower arch to be moved forward or advanced from where it ideally is supposed to be which makes the mandible be positioned in a forward direction and encourages it to be advanced with growth. In other words, the mandible is forced to grow forward into a more ideal position, relative to the maxilla, which corrects an excessive overjet. The overjet is also a difficult problem to correct and this procedure makes it easier for the orthodontist in his or her treatment of the patient.
The appliance of the present invention can correct overbite, overjet and rotations and crowding in a very short period of time (three to six months depending on the severity of the problems) which is then to be followed by a fixed appliance, that is, permanent brackets placed on the teeth by an orthodontist. The present appliance can then continue to be worn by the patient, but by the placement of bands or brackets fixed to the most posterior teeth (the first or second adult molars) with arch wires, their vertical eruption is stopped and no further overbite is or will be corrected. The overjet, however, will still be corrected, if needed, by the relation of the upper and lower jaws of the patient. This correction has nothing to do with the eruption of the teeth. When the overjet is properly corrected, the correction simply stops, even though the wear of the appliance continues.
According to a method of the present invention, the appliance is worn after the braces go on to the patient and the soft material and thinness of the outer margins allow the appliance to fit over the brackets without trimming. Therefore, the outer margins, especially the labial and buccal margins are thinned to be more pliable, particularly since the plastic is so soft.
In an embodiment, an extra amount of interference is provided in the front of the hinge portion of the appliance to cause interference when the opened appliance is attempted to be closed. This allows the hinge portion to be quite resistant to closure even though the material is so soft. This keeps the appliance open when the patient opens his or her mouth while sleeping, and tends to keep the appliance in constant contact with the front teeth while the patient is asleep. This improves tooth and jaw movement and is critical to being able to straighten the teeth while sleeping.
The present invention will also accept additional plastic or rubber denture lining materials (vinyl or latex, etc. liners) to be put inside the appliance to increase the hold on the teeth once the straightening is complete, or these materials can be placed in areas that are already straight while others continue to be straightened.
The use of additional materials, such as denture powder or other similar materials that increase the stickiness of the appliance to the teeth at night can be used for further enhancing the stickiness of the appliance.